Sir Elton John and David Furnish have welcomed their second baby via surrogate, sources tell The Post’s Los Angeles correspondent Richard Johnson. The couple are said to have had their second child with the same surrogate mother who bore their first son, Zachary, on Christmas Day 2010. Sources further said the same California-based woman — whose identity is being kept secret — also gave birth to Camille Grammer’s kids. But Elton’s rep Fran Curtis has refused to confirm or deny the new arrival. She told us, “We never discuss our clients’ personal lives,” even while she negotiates with US Weekly for another cover story.